Indentation modulus and hardness of Pb(Zr, Ti)O3 sol–gel films deposited on Pt and LaNiO3 electrodes: An estimation of the CijD compliances

Sol–gel PZT thin films with different crystalline orientations function of the deposit parameters such as: the nature (TiOx/Pt or LaNiO3) and the thickness of the bottom electrodes, the nature of the precursor solutions and the thickness of the final films, have been fabricated. These parameters affect the crystallite orientations, which has been determined by X-ray diffraction. Nano-indentation tests coupled with continuous stiffness method allowed to obtain the indentation elastic modulii measured under load M〈h k l〉 or at almost null load Mo〈h k l〉 (that is when the ferroelectric domains are or are not oriented with the stress) and the hardness Hb〈h k l〉 of these ceramics. From the present study and from the literature, the mechanical properties of these films are shown dependent on the crystalline orientation. A compilation of all the reported data allows values of M〈h k l〉, Mo〈h k l〉 and Hb〈h k l〉 to be proposed for the three characteristic orientations (0 0 1), (1 1 1) and (1 1 0). From these values and acoustic pico-second experiments, possible values of CijD and CoijD have been proposed.